Planters or seed drills have disk assemblies for continuously opening a furrow for deposit of seed. For example, see U.S. Pat. No. 4,030,428 to Truax issued June 21, 1977. The disk assemblies are commonly held in furrowing relationship to the ground by spring loaded pressure rod assemblies. A pressure rod bar has a lower end assembled to the disk assembly. The upper end engages a pressure rod arm and is free to move. A compression spring bears between the pressure rod arm at the upper end and the disk assembly at the lower end, biasing the disk assembly down but permitting upward deflection upon encountering an obstacle. The pressure rod assembly type of system requires periodic maintenance and replacement of numerous parts.